; Audi A6 4th Gen (C7/4G)* Original radio options - InCarTec

There are multiple original radio options in the Audi A6 4th Gen (C7/4G)*, which option is the original fitted system?

Enclosed Subwoofers/ Drivers Enclosed Subwoofers/ Drivers
Extra Slim Subwoofers Extra Slim Subwoofers
Spare Wheel Subwoofers Spare Wheel Subwoofers
Underseat Subwoofers Underseat Subwoofers